Link adaptation presents challenges in coordinated multipoint transmission (CoMP) networks in the context of wireless communications. Specifically, this disclosure may provide a framework for esitmating channel state information (CSI) at a communication receiver, such that the CSI estimate remains a reliable and robust metric for link adaptation (LA) purposes even in the presence of interference.
Communication systems may employ non-data reference signals (RS) of known pattern to assist receivers in CSI estimation for downlink (DL) channel quality assessment. In a CoMP network, network capacity and user equipment (UE) throughput (TP) are meant to be optimized by intelligently coordinating activities across multiple cooperating transmitters. Controlling a multitude of transmitters may require multiple instances of CSI estimates in order to allow the network the selection of which transmitter(s) to use on the DL, and their respective configurations, e.g., modulation and coding scheme (MCS) selection.
The UE may be asked to have its measurements based on separate sets of resource elements (RE) for each CSI estimate, with noise and interference conditions being potentially substantially different among these RE-sets, as well as independent from the noise and interference situation seen on the data signal. Interference not present on REs designated for a particular CSI estimate, despite seen potentially relevant for the TP optimization of the data signal, will not be considered in certain CSI reporting. This may lead to sub-optimum CSI reporting, increased block error rate (BLER), and thus, reduced TP.